JPH0457015A - Display medium and display method - Google Patents

Abstract

PURPOSE:To easily realize a large area, and also, to reduce the power consumption, and moreover, to obtain a display medium of abundant colors and its display method by forming plural image areas by at least two kinds of high polymer liquid crystals of different liquid crystal phase temperatures on a substrate provided with a heating layer. CONSTITUTION:By executing an electric conduction for two seconds by 30V voltage to a heating layer 5 through an electrode 6, a display medium is heated to 110 deg.C, and thereafter, by quenching it to a room temperature by using a fan 7, all high polymer liquid crystals are led to a transparent state. In this case, the display medium looks transparent. Also, by a thermocouple provided on the surface of a substrate, a temperature of the surface of the substrate can be known. Subsequently, by executing an electric conduction for one minute by 30V voltage to the heating layer 5 with respect to the display medium, it is heated to 110 deg.C, and thereafter, it is quenched by the fan 7 until it becomes 80 deg.C, and thereafter, by leaving it as it is until it becomes a room temperature, it is cooled slowly and only a high polymer liquid crystal can be set to a scattered state, and a white liquid crystal image can be recognized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a display medium capable of displaying at least one type of large screen image for a long period of time, and a display method thereof.

[Prior Art] Conventionally, signboards have generally been used as display media intended to display large-screen images for a long time. However, when using a signboard, it is necessary to rewrite the image in order to change it, which requires a lot of time and cost.

Therefore, several methods have been proposed to facilitate quick image changes. Examples include large CRTs,
Examples include LCD televisions and Q boards (manufactured by Japan Advanced Products). Note that the Q board is a display medium that uses a cube with each side painted in a different color to display information by selecting the side to be displayed.

[Problems to be Solved by the Invention] However, large CRTs require a large glass container for display, which is expensive to process, and the electron gun used for display requires a large amount of power.

On the other hand, it is difficult to create a large display medium for liquid crystal televisions because it is difficult to increase the area of cells that hold liquid crystals. Furthermore, in order to maintain the color, the liquid crystal must be maintained under an electric field, which requires a large amount of power.

Furthermore, in the Q-board, each cube that makes up the screen is one pixel, so if the pixels are made smaller, the number of cubes that make up the screen increases, making control difficult. Furthermore, the types of colors that can be used are limited to the number of faces of a cube that constitutes a pixel.

The present invention has been made to improve the drawbacks of the prior art, and provides a display medium that can easily be made into a large area, has low power consumption, and is rich in color, and a display method thereof. The purpose is to

[Means for Solving the Problems] The present inventors used a display medium in which a plurality of images are formed using polymeric liquid crystals having different liquid crystal phase temperatures on a substrate provided with a --like heating element. By controlling the entire display medium to be cooled after heating, it is possible to display only one type of polymer liquid crystal, making it easy to increase the area, consume less power, and display a rich variety of colors. It was discovered that the medium can be easily created.

That is, the present invention is a display medium characterized in that a plurality of image areas are formed using at least two kinds of polymer liquid crystals having different liquid crystal phase temperatures on a substrate provided with a heat generating layer.

Furthermore, when recording on a display medium within the liquid crystal phase temperature of the polymer liquid crystal constituting an image, the present invention includes the steps of (a) heating the heat generating layer to heat the polymer liquid crystal above the liquid crystal phase temperature; ) This is a display method characterized by displaying a selected image by slowly cooling only the liquid crystal phase temperature range and rapidly cooling the other temperature ranges.

The present invention will be explained in detail below.

Examples of polymer liquid crystals that can be used in the present invention include:
Generally referred to as side-chain type polymer liquid crystals, which have a main chain of methacrylic acid polymer or siloxane polymer, etc., with pendant low-molecular liquid crystals attached, and are used in the fields of high strength, high elasticity, and heat-resistant fibers and resins. Examples include those generally referred to as main chain polymer liquid crystals such as polyester-based and polyimide-based liquid crystals, and those generally referred to as discotic liquid crystals. Examples of the phases of these polymeric liquid crystals include a smectic phase, a nematic phase, and a cholesteric phase. It is also possible to use a chiral smectic C phase of a ferroelectric polymer liquid crystal in which asymmetric carbon is introduced into these polymer liquid crystals.

Next, specific examples of the polymer liquid crystal used in the present invention are listed below, but the invention is not limited thereto. However, in the display medium of the present invention, two types of polymer liquid crystals with different liquid crystal phase temperatures (both types are used).
It is more preferable that the liquid crystal phase temperature ranges of the two adjacent polymer liquid crystals do not overlap. Actually, T of the liquid crystal on the low temperature side
When i5o and the Tg of the liquid crystal on the high temperature side are separated by 5° C. or more, switching between cooling and slow cooling can be easily performed, and temperature control is easy.

H3 (a) MW = 18,000 υ (b) (d) CH3 However, when m = 2, R = -OCH, (e) When m = 6, R = -OCHs (f) 95
℃ 101℃ Glass□Liquid crystal layer (N) Iso.

In the present invention, dichloroethane, DMF, tetrahydrofuran (TH
F) Acetone, ethanol, other polar or non-polar solvents, or a mixed solvent thereof can be used. However, these solvents may vary depending on factors such as their solubility with the polymer liquid crystal used, the material of the substrate on which they are coated or screen printed, their wettability with the surface layer provided on the surface of the substrate, and their film-forming properties. Needless to say, you have a choice.

Further, as the substrate, heat-resistant glass, heat-resistant plastic, or the like can be used. At this time, the substrate may be non-oriented or may be wiped in multiple directions with ethyl alcohol, but in either case it is preferable to use a substrate whose surface has been sufficiently freed from dirt.

Further, in order to obtain a desired color, a dichroic dye of any color can be mixed into the polymer liquid crystal. Examples of dichroic dyes include Mitsubishi Chemical LSY-116 (yellow), LSR-401 (magenta), and 5BL-
335 (cyan), same LSY-116 and S B L33
Examples include, but are not limited to, a mixture of No. 5 (green) and the like. A small amount of these dyes is mixed into a polymeric liquid crystal, and the liquid crystal exhibits coloring properties by leading the liquid crystal to a scattering state. At this time, the mixing amount is preferably 5 wt% or less, preferably 1 to 4 wt%. Furthermore, the amount of the solvent used is preferably 1 wt% or less.

Next, we will discuss the method for creating and displaying display media in the first section.
This will be explained using figures. FIG. 1 is an explanatory diagram showing an example of a display medium of the present invention. In FIG. 1, electrodes 6 made of copper are first provided on both ends of a heat generating layer 5 made of ITO (indium tin oxide) on a heat-resistant glass substrate 2 as shown in FIG. 2(a). Prepare. At this time, materials that can be used for the heat generating layer 5 include carbon, tungsten, etc. in addition to ITO. Electrode 6 is the second
In addition to the method shown in FIG. 2(a), it is also possible to arrange the electrodes alternately, as shown in FIG. 2(b). Aluminum, copper, iron, etc. can be used for the electrode.

At this time, methods for checking the temperature of the substrate include a method using a thermoster, a method using a thermocouple, and the like.

Next, after dissolving the polymer liquid crystal represented by formula (b) in dichloroethane as a solvent, a dry coating thickness of 10
I1. The liquid crystal image 9 is formed by screen printing to a size of approximately m. After that, the solvent is evaporated by leaving it in an atmosphere at 30° C. for 1 hour, and then a liquid crystal image 10 is formed by screen printing the polymer liquid crystal represented by the above formula (e) in the same manner.

Thereafter, the solvent was evaporated by leaving it in an atmosphere at 130° C. again for 1 hour, and then the liquid crystal images 9.10 were all brought to a transparent state by rapidly cooling to room temperature. At this time, the display medium appears transparent. In order to improve the contrast of the liquid crystal image, a color substrate may be used between the liquid crystal image and the substrate. Alternatively, the entire substrate may be colored with a pigment or the like. (FIG. 3(a) @Shi) Next, the display method will be explained. The display medium is heated to 130° C. by the heat generating layer and then cooled.

At this time, by slowly cooling only the liquid crystal phase temperature of the polymer liquid crystal that is desired to be scattered, and quickly cooling the other temperatures, it is possible to put only one of the liquid crystals in a scattering state and switch images. In this case, rapid cooling refers to cooling at such a speed that the polymer liquid crystal constituting the image is fixed in the isotonic phase state, and specifically, cooling can be performed forcibly using a fan or the like. On the other hand, slow cooling refers to cooling over a sufficient period of time for the liquid crystal to enter a scattering state.

Specifically, it can be cooled by leaving it at room temperature.

In the case of display media created as above, 130℃
By heating to 77°C and 101°C, and then slowly cooling to room temperature, only the polymer liquid crystal (b) can be brought into a scattering state, and liquid crystal image 9 can be confirmed ( (See Figure 3(b)). In addition, by heating to 130°C, slowly cooling to between 77°C and 101°C, and then rapidly cooling to room temperature, only the polymer liquid crystal (e) can be brought into a scattering state, making it possible to recognize the liquid crystal image lO. (See Figure 3(c)). Then again 13
By heating the liquid crystal to 0° C. and then rapidly cooling it to room temperature, the image can be erased by returning the entire liquid crystal to its original transparent state (see FIG. 3(a)). At this time, by providing a backlight behind the display medium and illuminating the display medium, the image can be recognized more clearly. Furthermore, by mixing dichroic dyes of arbitrary colors with the polymer liquid crystal, multicolor display can be performed.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 In FIG. 1, a transparent heat-resistant glass substrate 2 with a thickness of 5 mm is shown.
A substrate was prepared on which an aluminum electrode 6 was provided on ITO (indium tin oxide) as a heat generating layer 5 as shown in FIG. 2, and the equation (b) and (
Using a polymeric liquid crystal expressed by the f1 formula, an arbitrary image was screen printed on a heat-resistant glass using a printing machine, Print Gocco, manufactured by Riso Materials Co., Ltd., and coated to a thickness of lOILm.

Thereafter, the display medium is heated to 110° C. by applying electricity to the heat generating layer 5 through the electrode 6 at a voltage of 30 V for 2 seconds, and then rapidly cooled to room temperature using the fan 7, thereby making all the polymer liquid crystals transparent. lead. At this time, the display medium appeared transparent. In addition, JIS-
Using a type thermocouple, we were able to determine the temperature of the substrate surface.

Next, the display medium was heated to 110°C by applying electricity to the heat generating layer 5 at a voltage of 30V for 1 minute, rapidly cooled down to 80°C with a fan 7, and then slowly cooled by leaving it to reach room temperature. Only the polymer liquid crystal represented by the above formula (b) could be brought into a scattering state, and a white liquid crystal image could be recognized. After that, after heating it again to 110℃,
By slowly cooling to 80°C and rapidly cooling to room temperature, only the polymer liquid crystal represented by the above formula (f) becomes in a scattered state,
You can recognize different images. Furthermore, 110℃ again
By heating the liquid crystal to room temperature and then rapidly cooling it to room temperature, the image could be erased by making the entire liquid crystal transparent.

At this time, by providing a backlight behind the display medium and illuminating the medium, it was possible to recognize the image more clearly.

Note that during rapid cooling, cooling is performed by moving a fan on the back side of the display medium. The position of the cooling fan is not limited to the back, but may be any position that can efficiently cool the liquid crystal image.

Embodiment 2 FIG. 4 is an explanatory diagram showing another display medium of the present invention. In Figure 4, the substrate 1 has a diameter of 1 mm at every 2 mm in the vertical and horizontal directions.
An A4-sized heat-resistant plastic plate with a thickness of 1 mm and a hole in it was prepared. Then, the dichroic dye LSR-4 manufactured by Mitsubishi Chemical Corporation was added to the polymer liquid crystal represented by the formula (b) above.
bM (magenta) was prepared by mixing 2 wt% of 01. Similarly, bG (green) is obtained by mixing 1 wt% each of dichroic dyes LSY-116 and 5BL-335 in the polymer liquid crystal represented by formula (b), and bG (green) is obtained by mixing 2 wt% of LSB-335 into the polymer liquid crystal represented by formula (b). ) were created. and mixtures of polymeric liquid crystals and dyes bta, ba
, bB was imaged by pouring it into a hole in a heat-resistant plastic plate. After that, using the polymer liquid crystal represented by the above formula (f) and the above three types of dyes, fM
.

Different images were created by making three types of mixtures, f, , f, and pouring them into holes in a heat-resistant plastic plate.

Furthermore, the hole was covered with heat-resistant glass 2a. Then, the entire display medium is heated to 110'C by passing a current of 28V through the heat generating layer 5 for 1 minute, and then the fan (
All of the polymer liquid crystals were brought to a transparent state by rapid cooling using a liquid crystal (not shown). At this time, the surface temperature could be easily determined by using a surface thermometer. At this time, the heat generating layer 5 has a thickness of 100)1. m ITO was used. Next, the current is passed through the heat generating N5 again, and the substrate 1 is
By heating it to 10℃, rapidly cooling it with a fan until it reaches 80℃, and then leaving it to cool slowly until it reaches room temperature.b
it.

Only b, , bB were in the scattering state. At that time, by illuminating the display medium with the backlight 3, bM, ba
Since only the dye contained in , bB was absorbed, the image could be recognized. Next, the substrate 1 is heated again to IIO'C by the heat generating layer 5, and then slowly cooled to 80°C and then rapidly cooled to room temperature to generate fii, fa, fe.
Only the left side was in a scattered state. At that time, another image could be displayed by illuminating it with the backlight 3.

Thereafter, the substrate 1 was heated to 110° C. and then rapidly cooled to room temperature, thereby returning the polymer liquid crystal to its original transparent state and erasing the image.

Embodiment 3 FIG. 5 is an explanatory diagram showing another display medium of the present invention. In FIG. 5, 1 is a substrate, 3 is a backlight, 4 is a pixel, 5 is a heat generating layer, and 6 is an electrode.

In the figure, the substrate 1 is transparent glass, and the heat generating layer 5 has a thickness of
It is 100gm of ITO. In addition, dichroic dye LS manufactured by Mitsubishi Chemical Industries, Ltd.
R-401, LSY-116 and 5BL-335
1. / 1 mixture, a mixture of 2 wt % of any one of LSB-335 was processed into a fiber, and then coated with PUT (polyethylene terephthalate) to create a fiber with a diameter of 5 mm. Similarly, three types of fibers were similarly created using the polymer liquid crystal represented by the above-mentioned formula (f). Then, these fibers and PET (polyethylene terephthalate) were processed into fibers with a diameter of 5 mm and arranged on a substrate 1 as pixels 4 to create a display medium.

The display medium created in this way is placed on the heat generating layer 5 at 28°C.
After heating to 110°C by passing a current at V for 1 minute, cooling to 80°C and then slowly cooling to room temperature, only the liquid crystal fiber containing the polymeric liquid crystal represented by formula (b) is in a scattering state. It became. At this time, the image could be recognized by viewing the entire display medium while being illuminated by the backlight 3. At this time, the temperature of the substrate could be easily determined by measuring the voltage of a thermocouple provided within the substrate.

Furthermore, by heating the substrate 1 again to 110°C by the heat generating layer 5, slowly cooling it to 80°C, and then rapidly cooling it to room temperature, only the liquid crystal fiber containing the polymer liquid crystal represented by the above formula (f) is heated. was in a scattered state, and a different image could be displayed by illuminating the display medium with the backlight 4 and passing it through the diffuser plate.

Thereafter, by heating the display medium again to 110° C. and rapidly cooling it to room temperature, the original scattering state could be restored and the image could be erased.

Embodiment 4 FIG. 6 is an explanatory diagram showing another display medium of the present invention. In FIG. 6, 1 is a substrate, 3 is a backlight, 4 is a pixel, 5 is a heat generating layer, and 6 is an electrode.

Here, the substrate 1 is made of heat-resistant glass with a thickness of 2 mm, and the pixel 4 is made of P
Two types of ET film were coated with 10gm thick polymer liquid crystal to draw images, each was formed into a tape with a width of 1mm, and the tapes were arranged alternately with PET film sandwiched between them. . At this time, as the polymer liquid crystal, polymer liquid crystals expressed by the above-mentioned formulas (b) and (f) were used, ITO with a thickness of 1100 IL was used for the heat generating layer 5, and aluminum was used for the electrode 6.

A current of 28V is applied to the heat generating layer 5 created in this way.
The entire display medium was heated to 110° C. by flowing for a minute, and then rapidly cooled to make all the polymer liquid crystals transparent. At this time, the temperature of the substrate surface could be easily determined by using a surface thermometer.

Next, the substrate 1 was heated to 80° C. by the heat generating layer 5 and then slowly cooled to room temperature, so that only the polymer liquid crystal represented by the formula (b) was in a scattered state.

At this time, by illuminating the display medium with the backlight 3 and viewing it, the image could be recognized.

Furthermore, by heating the substrate 1 again to 110'C by the heat generating layer 6, cooling slowly to 80°C, and then rapidly cooling it to room temperature, only the polymer liquid crystal expressed by the above formula (f) becomes in a scattering state. Similarly, another image could be displayed by illuminating the display medium with the backlight 3.

Thereafter, the entire display medium was heated to 110° C. and then rapidly cooled to room temperature, thereby returning it to its original transparent state and erasing the image.

[Effects of the Invention] As explained above, according to the present invention, -
By using a display medium in which multiple images are formed using polymeric liquid crystals with different liquid crystal phase temperatures on a heating element of various types, it is easy to increase the area, consume less power, and improve color reproduction. It is possible to easily display a wide range of information.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing an example of the display medium of the present invention, Figures 2 (a) and (b) are explanatory diagrams showing how to arrange electrodes in the heat generating layer, and Figure 3 is an example of temperature control in the present invention. and FIGS. 4 to 6 are explanatory diagrams showing embodiments of the display medium of the present invention, respectively. 1...Substrate 2...Heat-resistant glass substrate 2a...Heat-resistant glass 3...Backlight 4...Pixel 5...Heating layer 6...Electrode 7...Fan 9, IO...・LCD image

Claims (2)

[Claims] (1) A display medium characterized in that a plurality of image areas are formed using at least two polymeric liquid crystals having different liquid crystal phase temperatures on a substrate provided with a heat generating layer. (2) When recording within the liquid crystal phase temperature of the polymer liquid crystal that constitutes an image on a display medium, (a) heating the heat generating layer to heat the polymer liquid crystal to a temperature higher than the liquid crystal phase temperature; and (b) the selected image. A display method characterized by performing display by slowly cooling only the liquid crystal phase temperature range and rapidly cooling the other temperature ranges.